U.S. electric-car maker Tesla Motors plans to go public soon, two sources familiar with the matter said, amid growing interest in green technology and battery-powered vehicles.

An IPO filing from the 6-year-old start-up, best known for its $109,000 all-electric Roadster, is expected any day, said one of the sources. The person did not give a specific time frame, although IPOs typically take several months.

Tesla spokesman Ricardo Reyes declined to comment on what he called "rumor or speculation."

Tesla Model S
Caroline McCarthy/CNET

Tesla would mark the first public offering from a U.S. automaker since Henry Ford's Ford Motor debuted its shares in 1956. The IPO represents a landmark in the resurgence of electric-car technology that most carmakers had dismissed as impractical until recently.

But the financial market turmoil following the collapse of Lehman Bros. in the latter half of 2008 virtually shut down the IPO market. The appetite for IPOs has picked up since mid-September this year with a robust pace of new filings.

Analysts have said that the success of A123, the first green-technology IPO this year, would encourage more venture capital-backed green companies to go public.

Tesla will compete with established automakers like Ford, General Motors, and Nissan Motor, all of which are racing to launch electric or plug-in hybrid vehicles. Tesla, by contrast, is a small player with a high-end market and limited production.

Venture funds back green cars
The carmaker is developing a second, lower-cost model, an electric sedan known as the Model S, which will have a base price of $49,900.

Tesla said in September it delivered 700 Roadsters since February 2008. The Roadster, which is built on a Lotus frame, can go from 0 to 60 miles an hour in less than four seconds, making it faster than a Porsche 911 or a Ferrari Spider.

The electric-car start-up was offered $465 million in low-cost loans by the U.S. Department of Energy to help build the new Model S. Tesla said it will build the new car in California.